Motorcycle backfiring makes quite the noise, everyone hears backfires from the bikes. The sound of it makes people leap and look at each other with instant gratification. You may wonder the reason behind motorcycle backfiring?
Motorcycle backfires if the engine performance is low. Sometimes motorcycles backfire at intakes. The most common backfire on motorcycles is the engine runs in the wrong direction – too heavy. The burning process cannot be thoroughly cooled, thus the resulting in backfire.
This article will discuss the various causes of motorcycle’s engine backfires and show some ways you can stop them.
What Causes Motorcycles To Backfire?
Motorcycles can backfire for varying causes, but some particular kinds are very common. It might have been your experience – The motorbike starts and runs fine but when the throttle turns on the bike, it turns back on or starts producing a loud popping sound. The backfire!
Below are the common reasons which result in motorcycle backfire:
- Intermittent Sparks Of Motorcycle Engine
During combustion, the spark plug is responsible for the ignition of the fuel and air. The firing timings and sequences of these devices should be accurate to maximize the performance of the system.
Fuel combusts with the spark plugs, if the timing is incorrect, it causes two main effects: it gives off unburned oil and secondly it causes powerlessness.
If you are experiencing some sudden loss of power when rolling your throttle (usually accelerating), an intermittent spark plug may be responsible.
Uncombusted fuel leaves the engine when an exhaust valve opens, causing combustion into the exhaust pipes with a turbulent flow causing an engine to backfire.
- Too Short Of Exhaust Pipe
Short exhausts tend to be difficult to maintain; in fact, most states have legislation on how much longer pipes you can keep because there can be popping and banging of short exhaust pipes.
Short pipes are usually 12 inches or less long which are intended for motorcycles and provide an easier-looking appearance if they are noisy.
If the exhaust pipe is too short, it often causes an unexpected exhaust backfire. Shorter exhaust pipes provide a desirable look, giving a simple small design on an automobile. However unless the pipe is less than 12 in, the risk is minimal. The tubes are generally short and do not come with an internal baffle.
- Backfiring on Deceleration
Backfires when decelerating is just a way to burn out fuels from within combustion chambers. Usually, it happens inside an exhaust pipe, which is primarily due to two reasons:
When this exhaust valve opens, the pressure increases causing a lean mix of fuel and air. Fuel and air continue to burn but slowly. The open exhaust carries the burned air fuel mixture in the exhaust system and explodes once the combustion has ended.
Second, a deceleration backfire occurs when fuel and air ratios aren’t right. When the combustion chamber cannot burn enough fuel in the fuel lines there is no chance the combustion chamber will start a fire.
- Backfiring on Acceleration
The engine that backfired at speed is probably caused due to an inefficient intake. The air filter may be affected by the leak that causes the air to flow into your engine. This additional oxygen doesn’t match how your motor vehicle operates and causes burnout problems that can lead to backburn.
A bad wiring issue can also be the cause. It is possible that the ignition system wiring has been damaged or the ignition system may malfunction. The speed on your motorcycle engine may have been changed to allow air to accumulate in the combustion engine.
- Poor Timing
Different bikes have different timings. There are two important timings: an electronic synchronizer and condenser point setup. Of the two timers, electronic has the greatest efficiency in time saving.
With electronic timings being introduced in the late 20th century, troubleshooting a faulty device becomes easy. This is due to the fact that very little can be tested on identifying any faults.
Electronic timing follows simple working principles. When a piston is compressed, the ignition coil sends a voltage signal, which results the cylinder head backfiring.
- Loose Exhaust Header Pipe
The headers of this exhaust system form the first part of the exhaust system. The exhaust is part of the exhaust valve which is connected directly to the motor body.
Wondering how an empty header pipe may cause backfire? Air flow from the exhaust tubes are divided into two series – low-pressure and high-pressure.
The exhaust head is the wire connecting the exhaust to the car directly to the engine and the exhaust head is the last two feet or a pipe if the pipe is disconnected or withdrawn.
Loose headstock may actually cause the problem due to its location directly behind the engines exhaust valve which releases hot fume immediately from the exhaust valve if burned.
You will notice an unusual sound considered as backfire due to disconnection of exhaust header and engine.
- Bad Fuel Pump
When the tank is dirty there can be a couple of things happening. It can provide too much fuel that it needs, causing the motor to run more efficiently. Some surplus fuel is released in the exhausts of motorcycles and combustion is followed.
This could happen as the tank is running on a lower capacity compared to its needs. Without sufficient fuel flow, the fuel injection system would be sluggish. A fuel pump with intermittent operation can cause power loss in some areas if there is lean air fuel mixture. The result would be the final result of a motorcycle backfiring.
- Too Little Fuel Engine Running Lean
Motorcycle engines can run lean unless fuel/air ratios are lower than their manufacturers recommended ratio. In simpler terms, a motorized car that has lower fuel consumption in cylinders runs lean.
The air filter should be replaced regularly with an efficient filter. The combustion process occurs when air flows through the tank. During combustion, fuel and oxygen are released from the exhaust, where they explode and burn.
You can always check if a bike’s cylinder system is failing to fill or a change in airflow in a motor vehicle’s air cylinder is necessary.
- Clogged Jets
The carburetor is composed from four components that give you a comfortable ride each time the motor is turned. But they are often blocked with dirt and burn too much fuel which prevents them from functioning effectively.
The component consists are:
- Pilot jet: It mainly controls fuel during idle.
- Jets: The fuel is controlled when turning the throttle from 50 to 99% power.
- Jet needle: This component controls the volume the engine uses to run when adjusting the throttle from 0 to 80.
- Needle jet: This is what the jet must be carrying when the throttle is turning from 15 to 60%.
- Excess Fuel (Engine Running Rich)
In a motorcycling engine, a specific ratio is needed for efficient combustion. This particular fuel / air ratio is selected by the motorcycle manufacturer after intensive research & testing. The timing of the valves is programmable by the engine control unit and a variety of other factors can affect this.
Fuel injection and air flow ratios are specified for older vehicles in the carburetors, which are mechanical machines. When there are more gases in the burning chamber than in the combustion chamber, the resultant burning is not sufficient for combustion. which then leads to a motorcycle backfire.
- Faulty Carburetor
If you like motorbike riding then you must keep it safe. So you must first test your carburetor a few times. It’s a task that must first happen whenever a car backfires. The fuel cannot flow easily in the wrong carburetor.
Eventually, the engine will run less fuel. Your vehicle may also backfire or fail. It’ll take some effort to clean up the carburetor for the proper pumping of fuel. Use a carburetor cleaning product for thorough removal of any debris and leave an accessible passage.
- Bad Fuel Filter
A fuel filter ensures no impure material can enter the cylinder. When the tank is not pumped on time, it can cause damage. My motorcycles require replacing a fuel filter at least twice a year.
On specialized bikes, it’s generally impossible to replace the filter. It’ll need replacing. A clogged fuel filter can cause varying symptoms in motorcycles showing reduced flow of fuel into their engine cylinders. One of those exhaust-backfires can cause some idling issues.
- Airbox Leaks
A common reason a car runs a little ragged is a leak in an airbox. A defective airbox increases air-fuel ratio due to too much air- fuel consumption.
Make sure the rubber packing inside the air bag is clean and the screw that holds both sides of the box tightly. Visually examine the airbox if there’s a crack in the box.
Frequently Asked Questions
Does Backfiring Mean Something Needs Fixing?
It isn’t necessarily. Sometimes the issue with a backfire can be solved with a single turn of a mixing screw. But backfire does not always need a simple solution.
Check only the easiest problems. If this is fixed in one screw, then you save a little time and money.
If the rear fire cannot stop, you may be asked for repairing your bike. You must look at all your search engines and find any unknown problems. You need to find the most affordable option first.
How To check Air-Fuel Mixture Without Opening The Carburetor?
You can check the carburetor to determine if the mixture of gas and fuel has been dissolved. Removing an ignition switch will change the rim color.
- If it looks grayish, that’s fine.
- It should be dark, so it’s not very rich.
- If it looks burnt and white, the tire will run lean.
To test the air-fuel mix in the air from the main jet you must start your motorbike on an open throttle for a while. Keep coasting until you stop removing the ignition plug.
The Final Word
Motorcycles that backfire sound like unburned gas from an exhaust pipe ignited by heat. There are multiple reasons – why does a motorcycle backfire?
A motorcycle engine may have air leaks, a dirty carburetor, shorter exhaust pipes, a clogged fuel filter, a rich air fuel mixture, excess fuel, dirty gas, and much more. All these factors may cause your motorcycle to produce a loud popping sound. Yes, motorcycles are loud, to discover other reasons why they are loud? click here.
All the above-mentioned issues are resolvable, the key to avoid loud pop sounds from your bike is to regularly maintain your bike. Keep a close eye on its upkeep and cleaning. Clean your filters and dirty carburetors regularly.